What makes us "human"? Yves Coppens and Pascal Picq were already addressing this question in their excellent and voluminous ”Aux Origines de l'humanité ”, Fayard, 2001.
An interesting experimental research analysing the capability of chimpanzees to transmit learned behaviours comes to confirm the idea Coppens and Picq were advocating: there seems to be a graduate differentiation rather than a radical one.
http://news.bbc.co.uk/2/hi/science/nature/4166756.stmAlso of interest in this research is the apparent resistance to change demonstrated by chimpanzees with regard to previously learned techniques.
Yours sincerely.
Paul
